This invention relates to a content sharing system wherein content data are shared between a plurality of content processing apparatuses.
Different from conventional analog content, digital content of music and so forth can be copied multiple times without suffering from any quality deterioration. Therefore, in recent years, with the progress of the popularization of the Internet and the increase in speed of operation and capacity of personal computers, illegal distribution, exchange, and so forth of content without its copyright owner's permission is increasing.
In order to prevent such illegal actions, a copyright management system, which utilizes a DRM (Digital Rights Management) technique that places limitations on the distribution and utilization of content, is being popularized. In a copyright management system of the type described, usually the number of copies of original content items is managed strictly to limit illegal copying, as proposed in the SDMI (Secure Digital Music Initiative) and so forth. One such copyright management system is disclosed in Japanese Patent Laid-Open No. 2003-296486 (hereinafter referred to as Patent Document 1).
Such a copyright management system, wherein the number of copies of original content items is managed strictly as described above, adopts such a configuration that an apparatus such as a content user's personal computer is connected to a management server when content is copied. The content management server manages the total number of copies and permits/rejects content item copying. Therefore, the performance of the content user's apparatus, the form of interconnection of a plurality of apparatuses, and so forth, are restricted. Besides, a copyright management process must be executed every time copying of content is performed, which is inefficient. Accordingly, the degree of content utilization freedom is low, and to a legal user of content (that is, to a person who pays a reasonable consideration to a content producing person and utilizes the content within a range of private use) the copyright management system design freedom is low and is inconvenient, particularly in a case where content is shared between a plurality of apparatuses.
Further, it is generally considered that people prefer a conventional communication system of analog content, which acknowledges limitless copying as long as the content is utilized for private use, to a system that strictly manages the total number of copies. Therefore, a digital content management system that provides the benefits of an analog content system is desired.